From the Guidelines
Morrison's pouch, also known as the hepatorenal recess, is a critical anatomical space located between the liver and the right kidney, serving as the most dependent portion of the peritoneal cavity where fluid tends to accumulate due to gravity. This space is of significant clinical importance, particularly in the context of trauma or intra-abdominal pathology, as it is often the first site where free fluid such as blood or ascites collects [ 1 ]. The hepatorenal recess is one of the four potential spaces examined in the right flank or perihepatic view during emergency ultrasound imaging, alongside the pleural space, subphrenic space, and the inferior pole of the kidney [ 1 ].
Clinical Significance
The detection of fluid in Morrison's pouch can be indicative of serious conditions such as internal bleeding, infection, or other pathological processes that require immediate medical attention. Therefore, it is an essential area to examine during abdominal ultrasound assessments, particularly in the Focused Assessment with Sonography for Trauma (FAST) exam.
Anatomical Borders
Anatomically, Morrison's pouch is bordered by key structures: anteriorly by the liver, posteriorly by the right kidney, medially by the inferior vena cava, and laterally by the right paracolic gutter. Understanding the precise location and borders of this anatomical space is crucial for clinicians performing abdominal examinations and interpreting imaging studies [ 1 ].
Ultrasound Examination
During ultrasound examination, the hepatorenal space can be visualized by angling the probe inferiorly, allowing for the detection of fluid accumulation in Morrison's pouch [ 1 ]. Proper adjustment of gain settings is necessary to ensure that the diaphragm and renal sinus fat appear white, while known hypoechoic structures appear black, facilitating the accurate identification of abnormal fluid collections.
Key Points
- Morrison's pouch is located between the liver and the right kidney.
- It is the most dependent part of the peritoneal cavity in the supine position.
- Fluid tends to accumulate here first in cases of internal bleeding or ascites.
- It is a critical area to examine in trauma patients or those with suspected intra-abdominal pathology.
- Ultrasound is a key diagnostic tool for detecting fluid in Morrison's pouch.
From the Research
Definition and Location of Morrison's Pouch
- Morrison's pouch, also known as the hepatorenal recess, is the intraperitoneal space in the supramesocolic compartment located between the right liver lobe and right kidney 2.
- It is a dependent location that can be involved by various pathological conditions, including fluid collections, infectious or inflammatory processes, and neoplasms 2.
Clinical Significance of Morrison's Pouch
- The presence of intraperitoneal fluid in Morrison's pouch can be an indicator of various conditions, such as ascites, inflammatory fluid, or blood 3.
- The "moon crescent sign" can be used to diagnose intraperitoneal fluid in Morrison's pouch, even with small fluid volumes 3.
- Free fluid in Morrison's pouch on bedside ultrasound can predict the need for operative intervention in suspected ectopic pregnancy 4.
Imaging and Diagnosis of Morrison's Pouch
- Various imaging modalities, including ultrasound and computed tomography (CT), can be used to evaluate Morrison's pouch and diagnose pathological conditions 2, 5, 6.
- Knowledge of the anatomy and boundaries of Morrison's pouch is essential for accurate assessment and diagnosis of intra-abdominal pathologies 6.
- The evaluation of Morrison's pouch can be complicated by distortion of anatomy due to large hematomas or other pathological conditions 5.